Hybrid actuation devices with electrostatic clutches

ABSTRACT

A hybrid actuation device including a first plate and a second plate coupled to the first plate, a shape memory alloy wire coupled to the first plate and the second plate, a bladder positioned between the first plate and the second plate, the bladder housing a fluid, a first fixed electrode coupled to the second plate, and a flexible electrode coupled to the first plate and extending along the first fixed electrode.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to U.S. Patent Application No.63/243,824, filed Sep. 14, 2021, for “Hybrid Actuation Device with anElectrostatic Clutch,” which is hereby incorporated by reference in itsentirety including the drawings.

TECHNICAL FIELD

The present specification generally relates to hybrid actuation devicesthat include shape memory alloy materials and an electrostatic clutch.

BACKGROUND

Current robotic technologies rely on rigid components, such asservomotors to perform tasks, often in a structured environment. Thisrigidity presents limitations in many robotic applications, caused, atleast in part, by the weight-to-power ratio of servomotors and otherrigid robotics devices. The field of soft robotics improves on theselimitations by using fluid-based actuators. For example, fluid-basedactuators may introduce fluid into and out of a volume to expand orcontract the fluid-based actuators to perform mechanical work on a load.However, fluid-based actuators require a large amount of voltage tooperate.

Accordingly, a need exists for improved actuation devices that reducethe amount of voltage required to operate.

SUMMARY

In one embodiment, a hybrid actuation device including a first plate anda second plate coupled to the first plate, a shape memory alloy wirecoupled to the first plate and the second plate, a bladder positionedbetween the first plate and the second plate, the bladder housing afluid, a first fixed electrode coupled to the second plate, and aflexible electrode coupled to the first plate and extending along thefirst fixed electrode.

In another embodiment, a hybrid actuation device including a first plateand a second plate pivotally coupled to the first plate, a bladdercomprising a compressible portion and an offset portion, the bladderhousing a fluid positioned between the first plate and the second plate,the offset portion of the bladder positioned apart from the first plateand the second plate, and a shape memory alloy wire coupled to the firstplate and the second plate. The shape memory alloy wire is configured tomove the first plate and the second plate between a non-actuatedposition and an actuated position when a current is applied to the shapememory alloy wire. When moving from the non-actuated position to theactuated position, the first plate and the second plate are pivotedtoward each other to compress the compressible portion of the bladderpositioned between the first plate and the second plate, and to expandthe offset portion of the bladder positioned apart from the first plateand the second plate.

In yet another embodiment, a method of operating a hybrid actuationdevice, the method including: actuating the hybrid actuation device, thehybrid actuation device includes a first plate and a second platecoupled to the first plate, a shape memory alloy wire coupled to thefirst plate and the second plate, the shape memory alloy wire configuredto move the first plate and the second plate from a non-actuatedposition to an actuated position, when in the actuated position, adistance between a distal end of the first plate and a distal end of thesecond plate being less than a distance between the distal end of thefirst plate and the distal end of the second plate when in thenon-actuated position, a bladder positioned between the first plate andthe second plate, the bladder housing a fluid, a first fixed electrodecoupled to the second plate, and a flexible electrode coupled to thefirst plate and extending along the first fixed electrode; and applyinga current to the flexible electrode and the first fixed electrodethereby electrostatically attracting the flexible electrode and thefirst fixed electrode together to hold the first plate and the secondplate in the actuated position..

These and additional features provided by the embodiments describedherein will be more fully understood in view of the following detaileddescription, in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The embodiments set forth in the drawings are illustrative and exemplaryin nature and not intended to limit the subject matter defined by theclaims. The following detailed description of the illustrativeembodiments can be understood when read in conjunction with thefollowing drawings, where like structure is indicated with likereference numerals and in which:

FIG. 1A schematically depicts a side view of a hybrid actuation devicein a non-actuated state, according to one or more embodiments shown anddescribed herein;

FIG. 1B schematically depicts a side view of the hybrid actuation deviceof FIG. 1A in an actuated state, according to one or more embodimentsshown and described herein;

FIG. 2A schematically depicts a perspective view of a hybrid actuationassembly having a plurality of hybrid actuation devices in anon-actuated state, according to one or more embodiments shown anddescribed herein;

FIG. 2B schematically depicts a perspective view of the hybrid actuationassembly of FIG. 2A in an actuated state, according to one or moreembodiments shown and described herein;

FIG. 3 schematically depicts a spacer disposed between adjacent hybridactuation devices of the hybrid actuation assembly of FIG. 2A, accordingto one or more embodiments shown and described herein;

FIG. 4 schematically depicts another hybrid actuation device with arectilinear shape, according to one or more embodiments shown anddescribed herein; and

FIG. 5 schematically depicts a control system for controlling operationof the hybrid actuation device of FIG. 1A, according to one or moreembodiments shown and described herein.

DETAILED DESCRIPTION

Embodiments described herein are directed to hybrid actuation devicesthat include a shape memory alloy (SMA) wire and an electrostaticclutch. A bladder housing a fluid, such as a dielectric fluid, ispositioned between and coupled to a plate pair comprising a first plateand a second plate that are hinged or otherwise coupled together alongan end of the plate pair. A portion of the bladder is positioned apartfrom a space between the first plate and the second plate such that anoffset region of the bladder is offset from a perimeter of the firstplate and the second plate of the plate pair. The SMA wire is coupled tothe plate pair. The SMA wire is configured to move the first plate andthe second plate between a non-actuated position and an actuatedposition such that application of a stimulant, such as current flow, inthe SMA wire contracts the SMA wire and closes the plate pair together,placing the hybrid actuation device in an actuated state. When the SMAwire contracts, drawing the first plate and the second plate togetherand placing the hybrid actuation device in the actuated state, the fluidis directed into the offset region of the bladder, expanding the offsetregion.

The hybrid actuation device also includes a flexible electrode thatextends along a first fixed electrode and a second fixed electrode. Anelectrode pinching spring compresses the first fixed electrode and thesecond fixed electrode to contact the flexible electrode. A holdingthread couples the first plate to a first end of the flexible electrodeand a tension spring is coupled to the second end of the flexibleelectrode. The tension spring contracts the flexible electrode when theSMA wire contracts and draws the plate pair together. Moreover, theflexible electrode and the fixed electrode electrostatically attractupon application of a voltage to hold the hybrid actuation device in theactuated state with the holding thread. This allows actuation (e.g.,contraction) of the SMA wire to cease while retaining the hybridactuation device in the actuated state. Various embodiments of thehybrid actuation device and the operation of which are described in moredetail herein. Whenever possible, the same reference numerals will beused throughout the drawings to refer to the same or like parts.

Referring now to FIGS. 1A and 1B, a hybrid actuation device 10 isschematically depicted in a non-actuated state (FIG. 1A) and an actuatedstate (FIG. 1B). The hybrid actuation device 10 may include a firstplate 12, a second plate 14, a bladder 16 at least partially positionedbetween the first plate 12 and the second plate 14, a shape memory alloy(SMA) wire 18 integrated within and extending between the first plate 12and the second plate 14, a flexible electrode 20, a first fixedelectrode 22, a second fixed electrode 24, a tension spring 26, and anelectrode pinching spring 28. The first plate 12 may include a proximalend 30 a, an opposite distal end 30 b, an inside surface 30 c, a sideedge 30 d, and an outside surface 30 e opposite the inside surface 30 c.The second plate 14 may include a proximal end 32 a, an opposite distalend 32 b, an inside surface 32 c, a side edge 32 d, and an outer surface32 e opposite the inside surface 32 c. The inside surface 30 c of thefirst plate 12 may be positioned to face the inside surface 32 c of thesecond plate 14. The proximal end 30 a of the first plate 12 may bepivotally coupled to the proximal end 32 a of the second plate 14 by ahinge 34. As such, the first plate 12 may pivot about the hinge 34relative to the second plate 14.

The bladder 16 may be coupled to the first plate 12, the second plate14, or both. The bladder 16 may be coupled to and positioned between theinside surface 30 c of the first plate 12 and the inside surface 32 c ofthe second plate 14. The bladder 16 may be coupled to the first plate 12and the second plate 14 by welding, stitching, adhesive, or the like. Inembodiments, the bladder 16 is positioned between the first plate 12 andthe second plate 14 without being coupled to either of the first plate12 and the second plate 14. The bladder 16 may house a fluid, such as adielectric fluid. A “dielectric” fluid as used herein is a medium ormaterial that transmits electrical force without conduction and as suchhas low electrical conductivity. Some non-limiting example dielectricfluids include perfluoroalkanes, transformer oils, and deionized water.The bladder 16 may comprise any flexible, inextensible, and non-solublematerial, such as biaxially oriented polypropylene. The flexiblematerial of the bladder 16 may allow the bladder 16 to elasticallydeform and change shape when subjected to a compressive force from thefirst plate 12 and the second plate 14.

The bladder 16 may include a compressible portion 40 and an offsetportion 42. The compressible portion 40 of the bladder 16 may bepositioned within a space between the first plate 12 and the secondplate 14, such that the compressible portion 40 is configured to becompressed between the first plate 12 and the second plate 14 when thehybrid actuation device 10 moves from the non-actuated state to theactuated state. The offset portion 42 of the bladder 16 may bepositioned apart from the space between the first plate 12 and thesecond plate 14 such that the offset portion 42 of the bladder 16 isoffset from a perimeter of the first plate 12 and the second plate 14.The perimeter of the first plate 12 may be defined by the distal end 30b of the first plate 12. The perimeter of the second plate 14 may bedefined by the distal end 32 b of the second plate 14. Accordingly, theoffset portion 42 may not be impeded from expanding when the first plate12 and the second plate 14 are drawn together, as shown in FIG. 1B. Whenthe compressible portion 40 is compressed by the first plate 12 and thesecond plate 14, the fluid within the compressible portion 40 of thebladder 16 may be displaced into the offset portion 42, therebyexpanding the offset portion 42.

In embodiments, the SMA wire 18 may include a first end 50 a and anopposite second end 50 b. The first end 50 a of the SMA wire 18 may becoupled to the side edge 30 d of the first plate 12. The second end 50 bof the SMA wire 18 may be coupled to the side edge 32 d of the secondplate 14. The SMA wire 18 may be coupled to the first plate 12 and thesecond plate 14 by fasteners, welding, stitching, adhesive, or the like.It should be understood that the hybrid actuation device 10 may includeany number of SMA wires 18, such as, for example, a pair of SMA wires 18disposed on opposing sides of the first plate 12 and second plate 14. Inembodiments, the hybrid actuation device 10 may include more than twoSMA wires 18, such as three, four, etc. As discussed in more detailherein, the SMA wires 18 may extend throughout and between both thefirst plate 12 and the second plate 14. The SMA wire 18 may beconfigured to move the first plate 12 and the second plate 14 from anon-actuated position to an actuated position. In the actuated position,a distance between the distal end 30 b of the first plate 12 and thedistal end 32 b of the second plate 14 is less than a distance betweenthe distal end 30 b of the first plate 12 and the distal end 32 b of thesecond plate 14 when in the non-actuated position. When the first plate12 and the second plate 14 are in the actuated position, the hybridactuation device 10 is in the actuated state. When the first plate 12and the second plate 14 are in the non-actuated position, the hybridactuation device 10 is in the non-actuated state.

The SMA wire 18 comprises a SMA material configured to contract inresponse to a stimulant, such as heat, current, or a magnetic field. Inoperation, a stimulant, such as the inducement of current flow withinthe SMA wire 18 may be applied to the SMA wire 18 by a power source,which is electrically coupled to each SMA wire 18. In operation,applying the stimulant to each SMA wire 18 contracts the first end 50 aand the second end 50 b of each SMA wire 18 toward each other, therebydrawing the first plate 12 and the second plate 14 together. Drawing thefirst plate 12 and the second plate 14 together moves the hybridactuation device 10 from the non-actuated state, as shown in FIG. 1A, tothe actuated state, as shown in FIG. 1B. Moving the first plate 12 andthe second plate 14 from the non-actuated position to the actuatedposition pivots the first plate 12 about the hinge 34 relative to thesecond plate 14. The SMA wire 18 may comprise (i) silver-cadmium, (ii)gold-cadmium, (iii) cobalt-nickel-aluminum, (iv) cobalt-nickel-gallium,(v) copper-aluminum-beryllium and at least one of zirconium, boron,chromium, or gadolinium, (vi) copper-aluminum-nickel, (vii)copper-aluminum-nickel-hafnium, (viii) copper-tin, (ix) copper-zinc, (x)copper-zinc and at least one of silicon, aluminum, or tin, (xi)iron-manganese-silicon, (xii) iron-platinum, (xiii) manganese-copper,(xiv) nickel-iron-gallium (xv) nickel-titanium, (xvi)nickel-titanium-hafnium, (xvii) nickel-titanium-palladium, (xviii)nickel-manganese-gallium, (xix) titanium-niobium, or any combinationthereof.

The first fixed electrode 22 may include a first electrode portion 60and a first insulation layer 62 coupled to the first electrode portion60. The first electrode portion 60 of the first fixed electrode 22 maybe coupled to the outer surface 32 e of the second plate 14. The firstinsulation layer 62 may extend over the first electrode portion 60 suchthat the outer surface 32 e of the second plate 14 and the firstinsulation layer 62 enclose the first electrode portion 60. The firstinsulation layer 62 may include an outer surface 64 opposite the firstelectrode portion 60. In embodiments, the first insulation layer 62 mayextend over the first electrode portion 60 to entirely enclose the firstelectrode portion 60.

The second fixed electrode 24 may be positioned at a side of the firstfixed electrode 22 opposite the second plate 14, such that the firstfixed electrode 22 is positioned between the second plate 14 and thesecond fixed electrode 24. The second fixed electrode 24 may include asecond electrode portion 68 and a second insulation layer 70 coupled tothe second electrode portion 68. The second insulation layer 70 mayextend entirely over the second electrode portion 68. The secondinsulation layer 70 may include a first outer surface 76 a and anopposite second outer surface 76 b. The second insulation layer 70 mayextend over the second electrode portion 68 such that the secondinsulation layer 70 encloses the second electrode portion 68. Inembodiments, the second insulation layer 70 may extend only partiallyover the second electrode portion 68 to partially enclose the secondelectrode portion 68.

In embodiments, the hybrid actuation device 10 may include any number offixed electrodes, such as, for example, one, two, three, four, or morethan four. In embodiments including a single fixed electrode, the fixedelectrode may be coupled to the outer surface 32 e of the second plate14 with the flexible electrode 20 extending along the fixed electrode.The tension spring 26 may be positioned near the proximal end 32 a ofthe second plate 14 to maintain tension on the flexible electrode 20. Inembodiments including more than two fixed electrodes, the fixedelectrodes may be stacked, with the flexible electrode 20 extendingalong and wrapping around the plurality of fixed electrodes. Theadditional fixed electrodes increase the electrostatic attraction forcebetween the fixed electrodes and the flexible electrode 20.

Each of the first insulation layer 62 and the second insulation layer 70may include a polymer tape to adhere the first insulation layer 62 tothe first electrode portion 60 of the first fixed electrode 22, and thesecond insulation layer 70 to the second electrode portion 68 of thesecond fixed electrode 24. The insulation layers 62, 70 may additionallybe formed from an insulating material such as, for example,polyethylene, cross-linked polyethylene, Kapton®, Teflon®, rubber,silicon, polyvinyl chloride, modified ethylene tetrafluoroethylene, orthe like.

Each of the first fixed electrode 22, the second fixed electrode 24, andthe flexible electrode 20 may be formed of an aluminum-coated polyestersuch as, for example, Mylar®. One of the flexible electrode 20 and boththe first fixed electrode 22 and the second fixed electrode 24 is anegatively charged electrode, and the other of the flexible electrode 20and both the first fixed electrode 22 and the second fixed electrode 24is a positively charged electrode. For purposes discussed herein, eitherof the flexible electrode 20 or the fixed electrodes 22, 24 may bepositively charged so long as the other of the flexible electrode 20 orthe fixed electrodes 22, 24 is negatively charged. The flexibleelectrode 20 may comprise a jagged, zig-zag, or otherwise non-uniformshape to maximize surface area overlap between the flexible electrode 20and the fixed electrodes 22, 24. In operation, voltage may be applied tothe flexible electrode 20 and the fixed electrodes 22, 24,electrostatically attracting the flexible electrode 20 and the fixedelectrodes 22, 24 together.

The electrode pinching spring 28 may include a first end 72 a and anopposite second end 72 b. The first end 72 a of the electrode pinchingspring 28 may extend from the first fixed electrode 22 and the secondend 72 b of the electrode pinching spring 28 may extend from the secondfixed electrode 24 such that the electrode pinching spring 28 extendsbetween the first fixed electrode 22 and the second fixed electrode 24.The electrode pinching spring 28 may be formed of a biasing member, suchas a spring, that biases the first end 72 a of the electrode pinchingspring 28 toward the second end 72 b of the electrode pinching spring28. The electrode pinching spring 28 may bias the first fixed electrode22 toward the second fixed electrode 24 to compress the first fixedelectrode 22 against the second fixed electrode 24.

The flexible electrode 20 may include a first end 80 a and an oppositesecond end 80 b. The second end 80 b of the flexible electrode 20 may becoupled to the tension spring 26. The tension spring 26 may extend fromthe second end 80 b of the flexible electrode 20. The hybrid actuationdevice 10 may further include a platform 84. The platform 84 may becoupled to the distal end 32 b of the second plate 14, and extend in adirection opposite the first plate 12 such that an orthographicprojection extending from a first surface 86 of the platform 84intersects the first fixed electrode 22 and the second fixed electrode24. In other words, the platform 84 extends at least substantiallyperpendicular to the first plate 12 and the second plate 14. The tensionspring 26 may be coupled between the second end 80 b of the flexibleelectrode 20 and the first surface 86 of the platform 84. The tensionspring 26 may apply a biasing force biasing the second end 80 b of theflexible electrode 20 toward the platform 84.

The flexible electrode 20 may extend between the first fixed electrode22 and the second fixed electrode 24. The flexible electrode 20 may becompressed between the first fixed electrode 22 and the second fixedelectrode 24 by the electrode pinching spring 28. The flexible electrode20 may contact the outer surface 64 of the first insulation layer 62 ofthe first fixed electrode 22 and the first outer surface 76 a of thesecond insulation layer 70 of the second fixed electrode 24. Theflexible electrode 20 may wrap around an end of the second fixedelectrode 24 and extend in contact with the second fixed electrode 24along the second outer surface 76 b of the second insulation layer 70.Contact of the flexible electrode 20 with the second outer surface 76 bof the second insulation layer 70 is maintained by the biasing forcefrom the tension spring 26 biasing the second end 80 b of the flexibleelectrode 20 toward the platform 84.

The hybrid actuation device 10 may further include a holding thread 88.The holding thread 88 may be coupled between the flexible electrode 20and the first plate 12 to couple the flexible electrode 20 to the firstplate 12. The holding thread 88 may be formed of a material such as, forexample, Kevlar®. The first end 80 a of the flexible electrode 20 may becoupled to the holding thread 88. The holding thread 88 may extend fromthe first end 80 a of the flexible electrode 20 to the first plate 12.

The platform 84 may include a pulley 90 around which the holding thread88 or the flexible electrode 20 passes, thereby redirecting the holdingthread 88 and/or the flexible electrode 20 between the first fixedelectrode 22 and the second fixed electrode 24. The pulley 90 may bepositioned to guide the holding thread 88 and/or the flexible electrode20 and alter a direction of the holding thread 88 and/or the flexibleelectrode 20 to facilitate contact between the first plate 12 and theflexible electrode 20. The holding thread 88 may extend from the firstplate 12 over the pulley 90 such that the flexible electrode 20 does notcontact the first plate 12, the bladder 16, the second plate 14, or thepulley 90. In embodiments, the hybrid actuation device 10 does notinclude a holding thread 88, such that the flexible electrode 20 may bedirectly attached to the first plate 12.

Referring to FIGS. 2A and 2B, a perspective view of a hybrid actuationassembly 100 is depicted. The hybrid actuation assembly 100 may includea plurality of hybrid actuation devices 10 arranged about a central axis102. The hybrid actuation assembly 100 may include any number of hybridactuation devices 10, such as, for example, one, two, three, four, ormore than four. In embodiments including four actuation devices 10, asshown in FIGS. 2A and 2B, the hybrid actuation devices 10 may be shapedas a quadrant of a circle, such that the distal end 30 b of the firstplate 12 and the distal end 32 b of the second plate 14 come to a point.The proximal end 30 a of the first plate 12 and the proximal end 32 a ofthe second plate 14 may be rounded, and act as a perimeter of the circledefined by the plurality of hybrid actuation devices 10. The hybridactuation assembly 100 may include a central opening 104 concentric withthe central axis 102 and extending through each of the hybrid actuationdevices 10. The central opening 104 may expose the bladder 16 to allowthe bladder 16 to expand and contract through the opening when thehybrid actuation devices 10 move between the non-actuated state (FIG.2A) and the actuated state (FIG. 2B). The plurality of hybrid actuationdevices 10 may include a singular bladder 16, or in some embodiments, aplurality of bladders 16 in a stacked arrangement, positioned andextending between the first plate 12 and the second plate 14 of each ofthe hybrid actuation devices 10.

Referring now to FIGS. 2A-3 , the hybrid actuation assembly 100comprises a plurality of SMA wires 18 coupled to the adjacent hybridactuation devices 10 in a concentric annular pattern. For example, thefirst plate 12 and the second plate 14 of each of the plate pairs 30includes a plurality of grooves 27 positioned in a concentric annularpattern and the plurality of SMA wires 18 are positioned in theplurality of grooves 27. In addition, adhesive layers 29 are positionedover the grooves 27 to hold the plurality of SMA wires 18 in theplurality of grooves 27. As shown in FIG. 3 , a spacer 31 may bedisposed between adjacent hybrid actuation devices 10. The spacer 31 maybe acrylic, however other materials are contemplated. The spacer 31helps to align and organize the plurality of SMA wires 18. For example,the spacer 31 includes a plurality of spacer holes 33. The plurality ofSMA wires 18 may be threaded through the plurality of spacer holes 33.In the hybrid actuation assembly 100, the plurality of SMA wires 18 maybe coupled to adjacent hybrid actuation devices 10 in an over/underthread pattern. For example, a first SMA wire 18A may be coupled to afirst plate 12 of a hybrid actuation device 10 of the plurality ofhybrid actuation devices 10 and a second plate 14 (not pictured in FIG.3 ) of a second hybrid actuation device 10 of the plurality of hybridactuation devices 10 and a second SMA wire 18B may be coupled to asecond plate 14 (not pictured in FIG. 3 ) of the first hybrid actuationdevice 10 of the plurality of hybrid actuation devices 10 and a firstplate 12 of the second hybrid actuation device 10 of the plurality ofhybrid actuation devices 10.

Referring now to FIG. 4 , another embodiment of a hybrid actuationdevice 10′ is depicted. As shown in FIG. 4 , the hybrid actuation device10′ comprising the first plate 12 and the second plate 14, whichcomprise a rectilinear shape. In FIG. 4 , the first SMA wire 18A and thesecond SMA wire 18B are positioned along opposite sides of the firstplate 12 and the second plate 14 in a threaded pattern along eachrespective side. Furthermore, the hinge 34 of the hybrid actuationdevice 10′ may comprise a Kevlar® thread.

Referring now to FIG. 5 , an actuation system 200 may be provided foroperating a hybrid actuation device or a hybrid actuation assembly, suchas the hybrid actuation device 10 or the hybrid actuation assembly 100,between the non-actuated state and the actuated state. Thus, theactuation system 200 may include a controller 202, an operating device204, a first power supply 206, a second power supply 214, and acommunication path 208. The various components of the actuation system200 will now be described.

The controller 202 includes a processor 210 and a non-transitoryelectronic memory 212 to which various components are communicativelycoupled. In some embodiments, the processor 210 and the non-transitoryelectronic memory 212 and/or the other components are included within asingle device. In other embodiments, the processor 210 and thenon-transitory electronic memory 212 and/or the other components may bedistributed among multiple devices that are communicatively coupled. Thecontroller 202 includes non-transitory electronic memory 212 that storesa set of machine-readable instructions. The processor 210 executes themachine-readable instructions stored in the non-transitory electronicmemory 212. The non-transitory electronic memory 212 may comprise RAM,ROM, flash memories, hard drives, or any device capable of storingmachine-readable instructions such that the machine-readableinstructions can be accessed by the processor 210. Accordingly, theactuation system 200 described herein may be implemented in anyconventional computer programming language, as pre-programmed hardwareelements, or as a combination of hardware and software components. Thenon-transitory electronic memory 212 may be implemented as one memorymodule or a plurality of memory modules.

In some embodiments, the non-transitory electronic memory 212 includesinstructions for executing the functions of the actuation system 200.The instructions may include instructions for operating the hybridactuation devices 10 or the hybrid actuation assembly 100 based on auser command. The processor 210 may be any device capable of executingmachine-readable instructions. For example, the processor 210 may be anintegrated circuit, a microchip, a computer, or any other computingdevice. The non-transitory electronic memory 212 and the processor 210are coupled to the communication path 208 that provides signalinterconnectivity between various components and/or modules of theactuation system 200. Accordingly, the communication path 208 maycommunicatively couple any number of processors with one another, andallow the modules coupled to the communication path 208 to operate in adistributed computing environment. Specifically, each of the modules mayoperate as a node that may send and/or receive data. As used herein, theterm “communicatively coupled” means that coupled components are capableof exchanging data signals with one another such as, for example,electrical signals via conductive medium, electromagnetic signals viaair, optical signals via optical waveguides, and the like.

As schematically depicted in FIG. 5 , the communication path 208communicatively couples the processor 210 and the non-transitoryelectronic memory 212 of the controller 202 with a plurality of othercomponents of the actuation system 200. For example, the actuationsystem 200 depicted in FIG. 5 includes the processor 210 and thenon-transitory electronic memory 212 communicatively coupled with theoperating device 204, the first power supply 206, and the second powersupply 214.

The operating device 204 allows for a user to control operation of thehybrid actuation devices 10 or the hybrid actuation assembly 100. Insome embodiments, the operating device 204 may be a switch, toggle,button, or any combination of controls to provide user operation. As anon-limiting example, a user may actuate the hybrid actuation devices 10or the hybrid actuation assembly 100 into the actuated state byactivating controls of the operating device 204 to a first position.While in the first position, the hybrid actuation devices 10 or thehybrid actuation assembly 100 will remain in the actuated state. Theuser may switch the hybrid actuation devices 10 or the hybrid actuationassembly 100 into the non-actuated state by operating the controls ofthe operating device 204 out of the first position and into a secondposition.

The operating device 204 is coupled to the communication path 208 suchthat the communication path 208 communicatively couples the operatingdevice 204 to other modules of the actuation system 200. The operatingdevice 204 may provide a user interface for receiving user instructionsas to a specific operating configuration of the hybrid actuation devices10 or the hybrid actuation assembly 100. In addition, user instructionsmay include instructions to operate the hybrid actuation devices 10 orthe hybrid actuation assembly 100 only at certain conditions.

The first power supply 206 may be electrically connected to the SMA wire18 to stimulate the SMA wire 18. Stimulating the SMA wire 18 may includeproviding a current to the SMA wire 18, heating the SMA wire 18, and/orapplying a magnetic field to the SMA wire 18. The SMA wire 18 isconfigured to contract in response to receiving stimulation from thefirst power supply 206. The contraction of the SMA wire 18 draws thefirst plate 12 and the second plate 14 together, thereby contracting thecompressible portion 40 of the bladder 16 and expanding the offsetportion 42 of the bladder 16. As the first plate 12 and the second plate14 are drawn together, the tension spring 26 contracts to pull theholding thread 88 and the flexible electrode 20, thereby minimizingslack between the fixed electrodes 22, 24 and the flexible electrode 20.The reduction of slack on the flexible electrode 20 helps facilitatestrong electrostatic attraction between the fixed electrodes 22, 24 andthe flexible electrode 20 when the fixed electrodes 22, 24 and theflexible electrode 20 are actuated.

The second power supply 214 may be electrically connected to theflexible electrode 20, the first fixed electrode 22, and the secondfixed electrode 24 to provide a current to each of the flexibleelectrode 20, the first fixed electrode 22, and the second fixedelectrode 24. When a current is applied to the flexible electrode 20,the first fixed electrode 22, and the second fixed electrode 24, theflexible electrode 20 is electrostatically attracted to each of thefirst fixed electrode 22 and the second fixed electrode 24. Theelectrostatic attraction between the flexible electrode 20 and the fixedelectrodes 22, 24 maintains the hybrid actuation device 10 in theactuated state. In particular, the electrostatic attraction pinches andholds the flexible electrode 20, thereby retaining tension on theholding thread 88 to retain the hybrid actuation device 10 in theactuated state. Thus, the fixed electrodes 22, 24 and the flexibleelectrode 20 operate as an electrostatic clutch. Once the fixedelectrodes 22, 24 and the flexible electrode 20 are drawn together byapplication of a current, the stimulant may be removed from the SMA wire18, expanding the SMA wire 18. However, the continued application ofcurrent to the fixed electrodes 22, 24 and the flexible electrode 20together retains the hybrid actuation device 10 in the actuated state.Thus, the electrostatic attraction of the electrodes 20, 22, 24 keepsthe hybrid actuation device 10 actuated without the negative thermalbuildup of prolonged actuation of the SMA wire 18.

In operation, when the hybrid actuation device 10 is actuated bycontracting the SMA wire 18, expansion of the offset portion 42 of thebladder 16 may produce a force of 25 Newton-millimeters (N.mm) per cubiccentimeter (cm³) of actuator volume or greater, such as 30 N.mm per cm³or greater, 35 N.mm per cm³ or greater, 40 N.mm per cm³ or greater, 45N.mm per cm³ or greater, 50 N.mm per cm³ or greater, 55 N.mm per cm³ orgreater, 60 N.mm per cm³ or greater, 70 N.mm per cm³ or greater, 80 N.mmper cm³ or greater, 90 N.mm per cm³ or greater, 100 N.mm per cm³ orgreater, 125 N.mm per cm³ or greater, or any value within a range havingany two of these values as endpoints. Moreover, as one example toillustrate the strength of the electrostatic attraction between theflexible electrode 20 and the fixed electrodes 22, 24, when actuatedwith a voltage of 70 volts, the flexible electrode 20 and the fixedelectrodes 22, 24 are pinched together with a strength sufficient toresist 8 N of shear force applied to the interface between the flexibleelectrode 20 and the fixed electrodes 22, 24.

Each of the first power supply 206 and the second power supply 214 maybe a rechargeable direct current power source. It is to be understoodthat the power supplies 206, 214 may be a single power supply or batteryfor providing power to the hybrid actuation devices 10 or the hybridactuation assembly 100. A power adapter (not shown) may be provided andelectrically coupled via a wiring harness or the like for providingpower to the hybrid actuation devices 10 or the hybrid actuationassembly 100 via the power supplies 206, 214.

In some embodiments, the actuation system 200 also includes a displaydevice 216. The display device 216 is coupled to the communication path208 such that the communication path 208 communicatively couples thedisplay device 216 to other modules of the actuation system 200. Thedisplay device 216 may output a notification in response to an actuationstate of the hybrid actuation devices 10 or the hybrid actuationassembly 100 or indication of a change in the actuation state of thehybrid actuation devices 10 or the hybrid actuation assembly 100.Moreover, the display device 216 may be a touchscreen that, in additionto providing optical information, detects the presence and location of atactile input upon a surface of or adjacent to the display device 216.Accordingly, the display device 216 may include the operating device 204and receive mechanical input directly upon the optical output providedby the display device 216.

In some embodiments, the actuation system 200 includes network interfacehardware 218 for communicatively coupling the actuation system 200 to aportable device 222 via a network 220. The portable device 222 mayinclude, without limitation, a smartphone, a tablet, a personal mediaplayer, or any other electric device that includes wirelesscommunication functionality. It is to be appreciated that, whenprovided, the portable device 222 may serve to provide user commands tothe controller 202, instead of the operating device 204. As such, a usermay be able to control or set a program for controlling the hybridactuation devices 10 or the hybrid actuation assembly 100 withoututilizing the controls of the operating device 204. Thus, the hybridactuation devices 10 or the hybrid actuation assembly 100 may becontrolled remotely via the portable device 222 wirelessly communicatingwith the controller 202 via the network 220.

It is noted that the terms “substantially” and “about” may be utilizedherein to represent the inherent degree of uncertainty that may beattributed to any quantitative comparison, value, measurement, or otherrepresentation. These terms are also utilized herein to represent thedegree by which a quantitative representation may vary from a statedreference without resulting in a change in the basic function of thesubject matter at issue.

While particular embodiments have been illustrated and described herein,it should be understood that various other changes and modifications maybe made without departing from the scope of the claimed subject matter.Moreover, although various aspects of the claimed subject matter havebeen described herein, such aspects need not be utilized in combination.It is therefore intended that the appended claims cover all such changesand modifications that are within the scope of the claimed subjectmatter.

What is claimed is:
 1. A hybrid actuation device comprising: a firstplate and a second plate coupled to the first plate; a shape memoryalloy wire coupled to the first plate and the second plate; a bladderpositioned between the first plate and the second plate, the bladderhousing a fluid; a first fixed electrode coupled to the second plate;and a flexible electrode coupled to the first plate and extending alongthe first fixed electrode.
 2. The hybrid actuation device of claim 1,wherein the shape memory alloy wire is configured to move the firstplate and the second plate from a non-actuated position to an actuatedposition, and wherein, when in the actuated position, a distance betweena distal end of the first plate and a distal end of the second plate isless than a distance between the distal end of the first plate and thedistal end of the second plate when in the non-actuated position.
 3. Thehybrid actuation device of claim 2, wherein an offset portion of thebladder is offset from a perimeter of the first plate and a perimeter ofthe second plate.
 4. The hybrid actuation device of claim 1, furthercomprising a second fixed electrode positioned at a side of the firstfixed electrode opposite the second plate, the flexible electrodeextending between the first fixed electrode and the second fixedelectrode.
 5. The hybrid actuation device of claim 4, further comprisingan electrode pinching spring extending between the first fixed electrodeand the second fixed electrode, the electrode pinching spring configuredto bias the first fixed electrode and the second fixed electrode towardone another.
 6. The hybrid actuation device of claim 4, wherein: thefirst fixed electrode comprises a first insulation layer, the secondfixed electrode comprises a second insulation layer, and the flexibleelectrode is disposed between the first insulation layer and the secondinsulation layer.
 7. The hybrid actuation device of claim 1, wherein theflexible electrode includes a first end and an opposite second end, thefirst end coupled to the first plate, the second end coupled to atension spring.
 8. The hybrid actuation device of claim 7, furthercomprising a holding thread extending between the first end of theflexible electrode and the first plate.
 9. The hybrid actuation deviceof claim 1, further comprising a hinge provided at a proximal end of thefirst plate and a proximal end of the second plate, the hinge configuredto pivotally couple the first plate to the second plate.
 10. A hybridactuation device comprising: a first plate and a second plate pivotallycoupled to the first plate; a bladder comprising a compressible portionand an offset portion, the bladder housing a fluid positioned betweenthe first plate and the second plate, the offset portion of the bladderpositioned apart from the first plate and the second plate; and a shapememory alloy wire coupled to the first plate and the second plate,wherein the shape memory alloy wire is configured to move the firstplate and the second plate between a non-actuated position and anactuated position when a current is applied to the shape memory alloywire, and when moving from the non-actuated position to the actuatedposition, the first plate and the second plate are pivoted toward eachother to compress the compressible portion of the bladder positionedbetween the first plate and the second plate, and to expand the offsetportion of the bladder positioned apart from the first plate and thesecond plate.
 11. The hybrid actuation device of claim 10, furthercomprising: a first fixed electrode coupled to the second plate; and aflexible electrode coupled to the first plate and extending along thefirst fixed electrode.
 12. The hybrid actuation device of claim 11,further comprising a second fixed electrode positioned at a side of thefirst fixed electrode opposite the second plate, the flexible electrodeextending between the first fixed electrode and the second fixedelectrode.
 13. The hybrid actuation device of claim 12, furthercomprising an electrode pinching spring extending between the firstfixed electrode and the second fixed electrode, the electrode pinchingspring configured to move the first fixed electrode and second fixedelectrode toward one another.
 14. The hybrid actuation device of claim11, wherein the flexible electrode includes a first end and an oppositesecond end, the first end being coupled to the first plate, the secondend being coupled to a tension spring.
 15. The hybrid actuation deviceof claim 14, further comprising a holding thread coupled between thefirst end of the flexible electrode and the first plate.
 16. The hybridactuation device of claim 11, wherein: the first fixed electrodecomprises a first insulation layer, the second fixed electrode comprisesa second insulation layer, and the flexible electrode is disposedbetween the first insulation layer and the second insulation layer. 17.The hybrid actuation device of claim 10, further comprising a hingeprovided at a proximal end of the first plate and a proximal end of thesecond plate, the hinge configured to pivotally couple the first plateto the second plate.
 18. A method of operating a hybrid actuationdevice, the method comprising: actuating the hybrid actuation device,the hybrid actuation device comprising: a first plate and a second platecoupled to the first plate; a shape memory alloy wire coupled to thefirst plate and the second plate, the shape memory alloy wire configuredto move the first plate and the second plate from a non-actuatedposition to an actuated position, when in the actuated position, adistance between a distal end of the first plate and a distal end of thesecond plate being less than a distance between the distal end of thefirst plate and the distal end of the second plate when in thenon-actuated position; a bladder positioned between the first plate andthe second plate, the bladder housing a fluid; a first fixed electrodecoupled to the second plate; and a flexible electrode coupled to thefirst plate and extending along the first fixed electrode, and applyinga current to the flexible electrode and the first fixed electrodethereby electrostatically attracting the flexible electrode and thefirst fixed electrode together to hold the first plate and the secondplate in the actuated position.
 19. The method of claim 18, wherein:actuating the shape memory alloy wire comprises one or more of:directing a current through the shape memory alloy wire; heating theshape memory alloy wire; and applying a magnetic field to the shapememory alloy wire.
 20. The method of claim 18, further comprising:removing the stimulant applied to the shape memory alloy wire whilemaintaining the current applied to the flexible electrode and the firstfixed electrode.